He, Yanbo
(2016)
Band Gap Structure of Two Dimensional Acoustic Metamaterials with Coated Double Hybrid Lattice.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Acoustic metamaterials (phononic crystals) have received much recent attention. Over time, several efforts were proposed to improve the structure in order to enlarge the band gap, lower the band gap frequency, and/or generate greater attenuation of vibration. In this document, a novel two dimensional acoustic metamaterial with Coated Double Hybrid Lattice (CDHL) is proposed. The structure makes use of both the Bragg Scattering Theorem and the Local Resonance Theorem. In the simulation, both a lower frequency band gap and a higher frequency band gap are obtained. According to the modal analysis and phase spectrum analysis, it is proved that the lower frequency band gap is due to local resonance between the double lead cores and the rubber coating. At the same time, the higher frequency band gap is generated as a result of the interaction of Bragg scattering and local resonance effect. The variation in maximum vibration attenuation with respect to the position of the double central lead core is also investigated. Excellent vibration attenuation is demonstrated using the proposed method. Later on, experiments are carried out both to validate the simulation and to prove the effectiveness of the proposed structure. The output signal is picked up approximately in the middle of the structure and the results have coincides with the simulation quite well. At the end of this document, several outlooks are stated.
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| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
25 January 2016 |
| Date Type: |
Publication |
| Defense Date: |
16 November 2015 |
| Approval Date: |
25 January 2016 |
| Submission Date: |
2 December 2015 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
109 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
acoustic metamaterials, band gap structure, vibration attenuation, Coated Double Hybrid Lattice, interference |
| Date Deposited: |
25 Jan 2016 16:09 |
| Last Modified: |
15 Nov 2016 14:31 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/26547 |
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